Homeland Security raises the national threat level to orange

LONDON » British authorities thwarted a terrorist plot to blow up several aircraft midflight between the United States and Britain using explosives smuggled in hand luggage, officials said today.

British Home Secretary John Reid said the alleged plot was "significant" and that terrorists aimed to "bring down a number of aircraft through midflight explosions, causing a considerable loss of life."

Police arrested a number of people overnight in London after a major covert counterterrorism operation that had lasted several months, but did not immediately say how many.

Hawaii airports affected

Passengers at Hawaii airports will undergo an additional security screening at boarding gates to ensure they don't take any liquids or gels onboard aircraft, state officials said late last night.

The announcement came as the U.S. Department of Homeland Security raised the threat level for flights within the U.S. or entering the country to high, or orange. The move stemmed from a reported terror plot in London.

Though coffee, soft drinks and other beverages will be available onboard planes, passengers are forbidden to bring aboard any liquids, state officials said.

"We don't want people canceling their flight reservations, we are not urging them not to fly," said Maj. Gen. Robert G.F. Lee, the state's adjutant general and director of Civil Defense. "We just want them to know that extra security precautions will be in place for their protection."

Passengers were advised to allow extra time for the additional security screening. Transportation Safety Administration officials suggested three hours for domestic and international flights, and two hours for interisland flights.